Sulphonation of organic compounds



Patented not. 19. 1944 $365,638 1 UNITED STATES PATENT OFFlCE s LPnoNA'rIoN :1 2.12m cowomsns George Felix Hennion, South liend, Ind, aasignor to 15.1. du Pont de Nemours & Company, Wil

min'gton, Del., a corporation of Delaware lilo Drawing.

organic compounds and especially to improved processes wherein boron trifluoride is contained in the reaction medium, thereby facilitating the manufacture of the sulphonated product.

ous stirring, for ninety minutes at which time 66 parts had been absorbed. Additional heating over boiling water for thirty minutes caused a 16 parts loss in weight. The sulphonated product was remarkably clear, homogeneous and only Application February 21. 1940, Serial No. 320.013

Claims. (01. 260-505) mildly yellow in color.

1.1 parts oi unsulphonated benzene was recovered, indicating that sulphonation was about 98% complete. The residual solution was limed, boiled It is among the objects of the present invenand filtered with suction. The fllter cake was tion' to provide improved processes for sulphonatleached three additional times with 500 part porins organic compounds of the aromatic and hetion Of hot w ter and. thefour solutions eVB-Ds erocyclic series. Another object ofthe invenorated to dryne ep ly. the pr p tes tion isto provide processes of sulphonation in 10 dried at d n y for cal ium which boron trifluoride is used to assist and aug- (calculated 11.3% for anhydrous and 10.75% for ment the reaction. Other objects of the inven- 11110110hiflill'att)-v T lys we as follows: tion will be apparent from the following disclo- Beach No. Saints Go The invention will be more fully set forth in v the following more detailed description which includes examplesthat are given asillustrative 35:2 a-4 gembodiments of the invention and not as limitaq M {1M4 tions thereof. Parts are expressed in parts by V 1.1 94 weight unless otherwise noted. I p

A control experiment was performed, omitting Example 1 sulphommn of phenolthe boron fluoride, and showed only 42% sul- One mole equivalent (94.0 parts) of phenol was P fltion. mixed with 117.6 parts (1.2 moles) of 100% sulphuric acid in a closed steel bomb. Boron fluo- Example sfsulphmafim toluene ride w Passed in until 11 D8118 mole) had 92 parts (1.0 mole) of toluene was sulphonated n adsorbed- The m and contents w with 104 parts (1.0 mole) of 94% sulphuric acid heated for 1 hour at C. in a boiling water as described in x m g The steam tm ath. The charge was then boiled with about 5 t indicated 9 reaction A sample of 750 parts of saturated salt solution (about 20%). cium salt was converted to the phenyl ester which The clear solution was filtered and aproduct melted at 5 a The product was therewas allowed to crystallizeout. After crystallizafore, chiefly the para-sulphonic acid, the phenyl tion the product was filtered and air-dried. The ester of which melts at 95-96 0, process yielded 162 parts of phenol sodium sulphonatewhich is equivalent to a yield of 82.6%. 35 Example ilm naphthalene (cold) The product contained 13.48% organic sulphur and 0.12% inorganic sulphur. The product was g g s gg zfifig t i gg 3 2:3: converted to the corresponding pam'methoxy' fluoride were passed into 1 56 mole parts of no.

a p sulphonamide which had a melting point of 103 thalene and 1 52 mole pm of sulphuric which proved; to be essential-1y para acid. This required eight hours and stirring was phenol sodium sulphona'te' continued for an equal period. The product was Example 2-Sulphgnaflon benzene diluted with water, neutralized with soda ash and allowed to crystallize. The first crop of crystals Into a three-necked container were placed 78 45 weighed 263 parts and was predominantly the parts (1.0 mole) of benzene and 104 parts (1.0 alpha-sulphonate since the amide made from mole) of 94% sulphuric acid. The container this compound melted at MS -147 C. as comwas equipped with a mechanical stirrer, reflux pared with the melting point of 150 C. as recondenser and inlet tube for boron fluoride. ported in literature. The second crop of crystals Gaseous boron fluoride was passed in, with vigor- 5o weighed 99.5 parts. This was recrystallized and gave 62 parts of sodium naphthalene sulphonate which was also found to be substantially the alpha isomer.

similar results were obtained at sulphonatlng sstorzrperaturesaslowaaaboutt'o'ii.

Upon diluting the prod-'- uct with water and distilling with steam, only and Deutsch.

.n'aphthylamine in the above Example 5--Sulph0nati0n of naphthalene (hot) The process described in Example 4. was repeated at 160-165 C. 48 parts of boron fluoride were absorbed in ninety minutes.

M. P. l74-175 C., as compared with the melting point of 177 C, as reported in literature. The

acid which was recovered asthe sodium salt weighed 323.5 parts as compared with a possible theoretical yield of 345 parts. The sulphonamide made from the product melted at 2l2-213 C.

which is the accepted melting point of the beta isomer.

Example 6-Disulphonation of carbazole Dilution with water gave 16 parts of b,b-dinaphthyl sulphone,

The deposit weighed 32 parts and contained 30.9% barium. The mother liquor was 'evaporated to crystallization and gave a second quantity of crystals which weighed 82.5 parts and contained 32.4% barium. The calculated barium -content of the disulphonate monohydrate is' Example 7-Disulph0na tion of dipltenyl Disulphonation of 38.5 parts (0.25 mole) of diphenyl with 53 parts (0.51, mole) of 94% sulphuric acid and 25.5 parts of boron fluoride gave a mixture containing both the 'mono'and disulphonic acids. These were separated effectively by the procedure of Latschinou (Ref. Latschinou,

Ber., 6, 194 (1873)) and then converted to their potassium salts. The products were identified through the derivatives recommended by Gabriel (Ref. Gabriel and Deutsch, Ben, 13, 386 (1880)).

Example 8Sulpho nation of b-naphthz lamine 36 parts of beta-naphthylamine were dissolved in hot dilute hydrochloric acid and treated with ari excess of sodium sulphate solution to precipitate theamine sulphate; ,The latter was filtered,

washed and dried for one hour with heating up to 100 C. The dried, powdered b-naphthylamine sulphate (48 parts, 0.2 mole) was sifted into 125 parts (1.3 moles) of well stirred 100% sulphuric acid held-at 50-55 C. The mixture was a'pasty semi-solid. Boron fluoride was thenpassed into the mixture with stirring whilst maintaining the temperature at 50-55 C. Themixture liquefied as the BF: was absorbed. After thirty minutes the product began to increase in viscosity and rather suddenly set .to a mass of small crystals.

The temperature was then raised to 100 C. and heating continued for an additional thirty minutesw The product again liquefied and more; boron trifiuo'ride was added. The crude product was then cooled and treated with 300 cc. of water. The mixture was made into a thin'paste by stirring and was then chilled overnight. The sulphonic acids were filtered oif and dried. The filtrate contained only a trace of sulphonic acid as shown by a nitrite value of only .045%' and no coupling value. The product was a mixture of mono and .disulphonic acids as well as a mixture of isomers. V

Similar results were obtained by using alpha procedure instead of beta naphthylamine; a

Example 9Disulph0natitm of naphthalene 128 parts (1.0 mole) of powdered naphthalene I were treated with 205.8 parts (2.1 moles) of 100% v sulphuric-acid and agitated to form a paste. '63

parts of boron fluoride were passed into th reaction mass with liberation of considerable heat. The charge was heated at 100 C. for ninet min- .utes. The product contained 17.29% organic sul-. phur and no inorganic sulphur. Thecalculated organic sulphur content for the disulphonated naphthalene is 22.2%.

'Example 10-Sulph0nation of 1,4-di-(p-toZuz' dino) -anthraquinone product was fi1tered,- washed with two thousand parts of 5% brine solution, and dried at -55 C.

The product contained 5.81% sulphur (calculated sulphur'content 'i'or the monosulphonic acid is 6.43%). A good yield was obtained.

Example 11- S'ulphonation of naphthalene an recovery of BF;

During a period of ninety minutes, 58 parts of boron fluoride were passed into a mixture of 192 parts (1.5 moles) of naphthalene and 158 parts- (1.51 'moles) of 94% sulphuric acid whilst the temperature was maintained at 160-l65 C. Five parts of water were added and the product was vacuum distilled. There was dbtained.80.5 parts of distillate, B. P. 83 C..at 23 mm. which was BF3.2H2O. The recovery was thus 90% of the theoretical. The residue was poured into water, yielding 21.5 parts of the insoluble sulphone which was treated in the usual way to convert it into the free-sulphonic acid form. In general the presence of boron tn'fluoride causes a more active sulphonation of all compounds of the aromatic and heterocyclic series. I

lar sulphonations does not give as good yields.

The presence of boron 'trifiuoride generally permits the use of lower, temperatures for agiven sulphonation, thereby providin the means to vary theratio of isomers. The presence of the catalyst is also beneficial in that for a given kind of sulphonation a large excess. of sulphuric acid is generally unnecessary'thus enabling a yield of the sulphonation product in a purerform and without the presence of undesirable by-products. The activating efiect of boron trifluoride is also manifested in that substantially stoichiometric proportions of the aromatic compound and sul-v phuric acid can be used when boron trifluoride is present whereas an excess of one of thecompounds is generally necessary when the catalyst is not present. Another advantage of the catalyst resides in the fact that for a. given sulphonatiozr. I

.the ,yieldis improved. Boron trifluoride can be' ascaese easily separated from thedesired sulphonatlon products. .The boron trifluoride which is separated from'the sulphonated product can also be easily recovered.

It is desirable to havepresent in the reaction medium during s'ulphonation at least .05 mole of boron trifluoride per mole of the organic compound which i being sulphonated but any excess of boron trifluoride above this amount can be used. Boron trifluoride has a beneficial effect at all temperatures which can be used for direct sulphonation of aromatic and heterocyclic organic compounds in liquid and semi-liquid phase. For a given sulphonation the necessary temperature to complete the reaction is lower in general than that which is needed to produce good yields of satisfactory product when boron trifluoride is not present. In general the sulphonation at a given temperature i more complete and more rapid when boron trifluoride is present in the reaction mixture. Boron trifluoride may be introduced into the reaction mixture in an anhydrous or an incompletely hydrated form. When high tem peratures or other circumstances cause undue losses of reaction products or of boron trifluoride, a closed reaction system can be usedand pressures at or above atmospheric pressure can be used without deleteriously affecting the action of boron trifluoride. Solvents. which are referred to in the specification and claims as inert solvents are those which do-not enter in the reaction or combine with the sulphonated products. Such inert solvents can be present in the reaction medium. Useful inert solvents are, for example,

tetrachlor ethane, nitro benzene and ethylene dichloride.

I'he beneficial effect of boron trifluoride is present with initial reactants which are hydrous as well as with those which are anhydrous; and

the sulphonation of all compounds ofthe aromatic, as well as those of the heterocyclic series, such as pyridine, xanthene, thioxanthene and the like, aresimilarly effected. Dehydrating agents may be present or absent. Although it is often convenient first to form a mixture of boron trifluoride and the material to be sulphonated, and to add this mixture to the sulphonating. agent, any manner of forming a mixture comprising until the benzene is mono-sulphonated, said boron.

1 action mixture at sulphonating temperatures until the organic compound is sulphonated.

group consisting of compounds of the'aromatic and heterocyclic series; and maintaining the reaction mixture at sulphonating temperatures until the organic compound i sulphonated, said boron trifluoride being present in amount which is equivalent to at least .05 mole of boron trifluoride per mole of the organic compound bein sulphonated.

3. In the process of making a sulphonated organic compound of the heterocyclic series by the action of sulphuric acid on a compound of said series, the step which comprises adding boron tri fluoride to the reaction mixture.

.4. In'the process of making a-sulphonatedcv ganic compound of the aromatic series by the action of sulphuric acid on a compound of said series, the step which comprises adding boron trifluoride to the reaction mixture.

5. In the process of making a sulphonated organic compound from the group consisting of the benzene and naphthalene series by the action of sulphuric acid on a compound of said series, the

step which comprises adding boron trifluoride to' the reaction mixture.

6. In the process of making a sulphonatedo'rganic compound of the benzene series by the action of sulphuric acid on a compound of said series, the step which comprises adding to thereactionmixture at least 0.05 mole of boron trifluoride per mole of the compound'being sulpho-.

nated.

,7. In the process of mono-sulphonating benzene, the steps which comprise making a mixture of benzene, and sulphuric acid in about equimolecular proportions, adding boron trifluoride to the reaction mixture, heating to'about C.

trifluoride being present in amount between about .05.,mole and about 1 mole per mole of benzene.

. 8. In the process of sulphonating naphthalene, the steps which comprise making a mixture of naphthalene and sufiicient sulphuric acid to these components can beused. -The process is especially valuable for sulphonating compounds of the benzene and naphthalene series, particularly benzene, naphthalene and naphthylamine.

From the'foreg'oing disclosure it will be recognized that the invention is susceptible of modii fication without departing from the spirit and mono-sulphonate the naphthalene, adding boron trifluoride and maintaining the temperature between about 0 and about C. until the naphphalene is sulphonated, said boron trifluoride being present during sulphonation from an equivalent to atleast .05 mole. I 9. In the process of sulphonating naphthylamine, the steps which comprise forming a reaction medium comprising sulphuric acid and the sulphateof the naphthylamine, passing-boron trifluoride into the reaction mixture during sulphonation and heating the mixture.

10. The process which comprises sulphonating an organic compound of the aromatic series with sulphuric acid in the presence of boron trifluoride.

' GEORGE,FELIX HENNION.

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